Green thread algae is the easiest to get rid of by using algae eaters, especially Amano shrimps.
I've tried almost all the recommended schemes:
Reducing fish feeding: didn't work.
Upping CO2: yes, I know it's hard to know if you are injecting enough of it. But it didn't work.
Frequent water change: 50% wc every other day for one full month. Didn't work. A good exercise, though.
Black out: 3 days. They came back.
Fertilisation: I've tried both doing full EI, and also tried stop dosing until the plants showed
deficiencies. Both didn't work.
Lighting: Very low light for 6 months, some plants died but algae didn't. I've stopped believing in low lighting since then.
Nothing worked, until I followed Tropica's guide about keeping 5 Amano shrimps per 5 litres.
http://tropica.com/en/guide/algal-control/
After bringing in 70 Amano shrimps into my 340 litre tank.
They've changed my tank from this.
To this.
Then it's dawn to me why most aquascapers in Asia don't need high flow rate,
large amount of ferts, or trying to find how much CO2 they can inject into the tank.
Algae?
Add more shrimps.
Having not enough budget to buy enough shrimps or the deadline is too close and can't wait for the shrimps to do the job?
Algicide. Then add as many shrimps as you can afford.
Their strategy about algae is simple: always keep the grazing pressure greater than algae's propagation rate.
After that, it's just conversation about plant deficiencies, rare or difficult plants, and scaping.